Siemens has expanded the Sitop power supply portfolio with the PSU100D switched-mode power supply systems. The new products are single-phase devices with an attractive price/performance ratio for direct mounting on a wall. Screw installation means that a mounting rail is not necessary. The rugged, low-profile aluminum casing with IP20 degree of protection requires little space and permits mounting in different positions. The devices meet all the basic requirements for a power supply and are particularly suitable for installation in apparatus and machines, as well as for use in automation solutions with no standard rail mounting. The temperature range from minus 10 to plus 70 degrees Celsius supports universal implementation even under harsh environmental conditions. The six fan-free variants of the power supplies provide a regulated supply of 24 volts with rated output currents ranging from 2.1 to 6.25 amperes (A) and 12 volts with 3 or 8.33 A. Another 24 V version with an output current of 12 A uses a fan for cooling purposes. For higher outputs, two devices of the same type can be connected in parallel. Single-phase connection to almost any public and industrial supply system is possible thanks to the wide-range input of 85 to 264 V AC, radio interference class B as well as certification in accordance with CE and cULus (Underwriters Laboratories certification for Canada and the USA). The output voltage can be set between 22 and 28 V using potentiometers in the 24 V variants, and between 11 and 14 V in the 12 V variant. A green LED indicates the operating status "Output voltage OK." Electronic short-circuit, overload and overvoltage protection features ensure safety in the event of a fault.